I was playing around with a simple recipe from Ben and Jerry's, and my wife was appaled at the amount of heavy cream required (2:1, cream:milk). The result was a very fatty ice cream that was delicious but made us have tummie aches due to eating too much. So I started fiddling with the proportions, and added some yogurt to add some creamyness. The result was a tangy vanilla that probably wouldn't remind you of yogurt at first taste-the yogurt seems to just bring out the other flavors well.